The Internet Protocol (“IP”) is an addressing protocol designed to route traffic within a network or between networks. The Internet Protocol is used on many computer networks including the Internet, intranets and other networks. Internet Protocol addresses are often assigned to “immobile” nodes on a network. An immobile node may be moved to a different computer network, but is typically associated with a static physical location and an immobile Internet protocol address.
Mobile IP protocols allow Internet users to retain the same IP addresses no matter what point of access they use to connect to the Internet. Two such mobile IP protocols are Mobile IPv4 and Mobile IPv6. The former is notable for its support only of the four-byte addresses used in Internet Protocol version 4, whereas the latter supports the sixteen-byte IP addresses that are coming into use with Internet Protocol version 6. Although IP version 6 has certain advantages over version 4—notably its expanded address space—the widespread use of Mobile IPv4 in some applications forestalls the conversion from Mobile IPv4 to Mobile IPv6. One such application is in networks using CDMA2000, the dominant wireless data technology in the United States and Korea. As IPv6 is deployed on other network nodes, however, it will become increasingly important for Mobile IPv4 networks to support the use of IPv6 nodes.
The operation of Mobile IPv4 is described in, for example, the Request for Comment (RFC) “IP Mobility Support,” RFC-2002 (October 1996), and “IP Mobility Support for IPv4,” RFC-3220 (January 2002), available from the Internet Engineering Task Force (www.ietf.org), the contents of which are incorporated herein by reference. The use of mobile IP in a CDMA 2000 network is described in the Telecommunications Industry Association interim standards “CDMA2000 Wireless IP Network Standard,” TIA.IS-835-B (September 2002), and “Interoperability Specification (IOS) for CDMA2000 Access Network Interfaces,” TIA/EIA/IS-2001.7-B (May 2002), the contents of which are incorporated herein by reference.